The effects of Cd on cancer stem cell-related signaling pathways have been addressed in Cd treated-MCF-7 and HepG2 cells, i.e. the activation of Ras/Raf/MEK/ERK signaling cascade (Ju et al., 2017) and the activation of MAPK/ERK signaling pathway in human lung adenocarcinoma cells (Huff et al., 2016). This evidence concerns the gene MAP2K7 and lung adenocarcinoma.